Testing apparatus for internal-combustion-engine ignition systems



G. L. HOGAN.

TESTING APPARATUS F 0R INTERNAL COMBUSTION ENGINE IGNITION SYSTEMS.

APPLICATION FILED JUNE 28, 1920.

1 372 75 1 o Patented Man 29 11921 2 SHEETS-SHEET I.

n H nu IIIII ZNVENTOR: eorge L. flog/ 90.

JETTO zPzYfxsf G. L. HOGAN.

TESTING APPARATUS FOR INTERNAL COMBUSTION ENGINE IGNITION SYSTEMS.

APPLICATION FILED JUNE 28,1920.

1,872,75 II 0 Patented Mar. 2;), 11921.,

2 SHEEIS-SHEEI 2.

' cylinder which is not functionin properly.

UNHTED stares caries.

-GEORG'E LEWIS HOGAN, 015 CHICAGO, ILLINOIS, ASSIGNOR 01E PINE-HALF T0 ALBERT H. MARSHALL, OF CHICAGO, ILLINOIS.

TESTING APPAT'US FOR INTERNAL-COMBUS'IION-ENGINE IGNITION SYSTEMS.

Specification of Letters Patent.

Patented Mar, 29, I921.

Application filed June 28, 1920. Serial No. 392,193.

To all whom it may concern:

Be it known that I, GEORGE LEWIS HOGAN, a citizen of the United States, residin at Chicago, in the county of Cook and tate of Illinois, have invented new and useful Improvements in Testing Apparatus for Internal Combustion Engine Ignition Systoms, of which the following is a specification.' v

This invention relates to apparatus for testing for or locating defects in the ignition system of motor vehicles and other internal-combustion engines having a plurality of cylinders and employing an electric spark to ignite the fuel charges, the spark being produced between the termlnals of spark plugs located in the engine cylinders.

By introducing an auxiliary spark gap in the circuit of each spark plug, it can be readily ascertained which one of the plugs is not firing properly or whlch circuit 1S defective. These devices, as usually designed, are objectionable for the followlng reasons.

1. The auxiliary or indicating spark being produced in the open atmosphere, and in proximity to the electrical connections generates ozone by the action of the spark on the oxy en of the atmosphere, and the action of tl ie ozone on the metalparts of the connections forms salts of such metals, which is very apt to cause short circuits under the high tension current employed,

2. The rapid succession of sparks in the several gaps makesit difiicult to locate the i 3. An auxiliary spark gap pro need in the open air introduces such a high resistance in the circuit that it often causes the spark to leap across to some other circuit as its path of least resistance, and particularly where the resistanceof that path has been diminished by the formation of oxid on the electrical connections bythe action of the ozone. 4. The push-button switches are usually so exposed that water is permitted toenter the instrument and prevent'the proper func tioning thereof. a

The object of the resent invention is' to overcome the diilicu ties hereinbefore enumerated, as well as to provide a very-simple device which can be mounted on the dashboard of the car, and by which any interruption of the ignition circuit can be almost instantly detected.

The object stated is attained by means of a novel combination and arrangement of parts to be hereinafter described and claimed, and in order that the same may be better understood, reference is had to the accompanying drawings forming a part of this specification.

In the drawings,

Figure l is an elevation of the apparatus; Fig. 2 is a vertical section on the line 2-2 of Fig. 1; Fig 3 is a longitudinal section and an end view of an indicating device operating in conjunction with the apparatus shown in Figs. 1 and 2; Fig. 4 is a longitudinal section of a different type of indicating device, and Fig. 5 is a diagrammatic view of the apparatus and the parts to which it is connected.

The invention is shown in connection with a four cylinder engine, a fragment of the cylinders bein shown at 10, and the spark plugs at 11, t e latter being grounded, as usual. The distributer is shown at 12 and the generator at 13. The testing device comprises the following parts 1 On the dashboard 14 of the car are mount-. ed two depending bracket arms 15, the same being secured by screws or other suitable fasteners 16. These arms 15 carry twp spaced plates 17 and 18 of insulating mate rial, the spacing being obtained by top and bottom spacer blocks 19, also of insulating material, and positioned between the plates at the corners thereof. This assembly of plates of insulating material is also provided with top and bottom metallic cover plates 20 and 21, and the front plate 17 has a metallic border plate 22 integral with the top and bottom cover plates. Screws 23 or other suitable fasteners, passing through the border plates 22, the plates 17 and 18, the blocks 19 and the bracket arms 15, hold the parts assembled, the bracket arms being behind the rear plate 18.

In the plate 17 are four pairs of apertures, the members of each of which are vertically spaced. These apertures extend entirely through the plate to open into the space between the same and the rear plate 18. The

of apertures are also numbered from 1 to 4,

corresponding to the number of cylinders 10. Inline with the apertures 24 and 25, the

rear plate carries a corresponding number of binding posts, the ones opposite the top apertures being denoted by the reference character 26, and those opposite the bottom apertures by the reference character 27. These binding posts are arranged in pairs, and each binding post carries at its inner end, in the space between the plates 17 and 18, a resilient bowed strip 28, extending over into contact with the plate 17 and seating with its free end against the innerface thereof over an aperture in said plate. Between each air of strips 28 is interposed a contact plhte 29 with which the free ends of said strips are also in contact, said plate 29 being secured to the inner face'of the plate 17. There is a separate plate 29 for each pair of strips 28. The conductors 30 leading from the distributer 12 are connected to the binding posts 26, and from the binding posts 27 conductors 31 lead to the spark plugs 11. The strips 28 are normally in contact with the plate 29, and hence the circuits of the several spark plugs are here completed.

From the .top plate 20 extend cylindrical guides 32 for plungers 33 having their lower ends ositioned to enter the space between the p ates 17 and 18 so as to come in contact with the top strips 28 and thus serve as grounding switches to ground the circuits of the plugs 11, it being understood that the plungers are rounded through themetallic parts of the evice. This operation is adwhich fits shdably over the guide 32.- a

vantageous in makin a test to ascertain if one or more of the cylinders 10 are misfiring and which cylinder it is. For instance, it

three of the plungers are pressed down simultaneously and I the engine thereupon stops it is evident that the cylinder correspon ing to the erator knows at once which cylinder it IS. The numbers of the apertures 24 and 25 are sociated with.

Each plun er 33 is carried by a cap 34 s ring 34: under the cap holds the plunger e evated normally, As the caps 34 telescope over the guides 32 they close the same and prevent water from getting between the plates 17 and 18.

The following means are provided for producing an auxiliary spark gap in the'circuit of any one of the spark fplugs 11 At 35 is shown a plug 0 insulating material having two projecting pins 36 of con-" ducting material. These pins are spaced so that they may be inserted into any one of the pairs of apertures 24: and 25, and when full inserted thpg engage'the strips 28 and pus the same 0 the plate 29, without the contact between the pins and the strips beplunger which was not pressed down, is misfiring, and by the number associated with the plun er, the o should be in ing broken. In'the face of the plug 35 is a socket in which seats a glass bulb 36 containing two sparking electrodes 37 electrically connected to the pins 36. It will therefore be seen that when the pins 36 are inserted into a pair of apertures 24 and 25, the electrodes 37 are interposed in the circuit of a corresponding spark plug 11, and the operation of the latter may be observed by the spark produced at the spaced terminals of the electrodes 37.

The electrodes 37 and the bulb 36 may be assembled in the same manner as an incandescent lamp, the bulb being screwed into the plug 35, or connected thereto in any other convenient manner to establish an electrical connection between the electrodes 37 and the pins 36. I

The bulb 36 is sealed, and itsinterior is evacuated; or it may contain any ofthe gases having a lower resistance than the normal atmosphere. The low resistance at the auxiliary spark gap therefore assures a Instead of a visual indicator, an audible indicator may beemployed, the same consisting of a buzzer 38 constructed similar to a telephone receiver, and carriedby a plug 39 having contact pins 40 operating in the same manner as pins 36. I

The audlble indicator may be used together with the visual indicator when two cylinders 10 are to be tested at the same time so that one indication is a spark at the auxiliary spark gap and the other a click at the buzzer plug, these being easily dis-1 tinguished from each other. The use of two distinct and difi'erent signals makes it very easy to locate trouble when the engine is running at high speed, there being no cona fusion by a rapid succession of sparks in several gaps.

Where one cylinder at a time'is to be tested, either one of the indicators may be used.

It will be noted that the index numbers 1 to 4 are applied to each row of apertures 24 and 25, the ones associated with the row .25 being shown inverted so that the device can be mounted u side down if the caps 34 e way of other fixtures on the dashboard 14 of the car.

The device is very simple, in construction, it can be easily installed and it is highl efiicient and reliable in operation. It wil also be understood that various changes and modifications in the structural details disclosed may be made without a departure from the spirit and scope of the invention as claimed hereinafter. lln'stead of providing a single indicating device and selectively interposing the same in the ignition circuits of the respective cylinders of the motor, a plurality of such devices may be providedone for each ignition circuit.

circuits of diilerent cylinders of the engine externally of said cylinders.

2. A testing apparatus for the ignition circuits of multiple-cylinder internal vcombustion engines, comprising pairs of movable contact members interposed in the ignition circuits of the respective cylinders, separate conductor plates normally bridging said pairs of members, and an electro-responsive indicating device having means for electrical connection with the respective pairs of contact members and for disengaging the same from the contact plates.

3. A testing apparatus for the ignition circuits of multiple-cylinder internal com bustion engines, comprising pairs of movable contact members interposed in the ignition c1rcu1ts of the respective cylinders, separate conductor plates normally bridging said pairs for engagement with corresponding contact.

members and for disengaging said members from their contact plates. 4. A testing apparatus for the ignition circuits of multiple-cylinder internal-combustion engines, comprising pairs of movable contact members interposed in the ignition circuits of the respective cylinders, separate conductor plates normally bridging said pairs of members, an electro-responsive indicating device having means for electrical connection with the respective pairs of contactmembers and for disengaging the same from the contact plates, and a grounding switch for each pair of contact members. lln testimony whereof I affix my signature.

GEORGE LEWIS HOGAN. 

